Oxitec has built a breeding lab in Marathon and hopes to release its mosquitoes in a Key West neighborhood this spring.

On the face of it, it sounds like a great idea, right? Male mosquitoes don’t bite, so, presumably, no genetically modified mosquitoes would be biting humans. And it could seriously reduce the mosquito population. Mosquitoes carry diseases that affect millions of humans a year, so this could be good. Except for one thing: these tampering tactics rarely have only one effect.

Think about pretty much any attempt by humans to manage natural imbalances by “exotic” means. Just look at Australia. Rabbits were released into the wild in the 19th century to provide “a touch of home, and a spot of hunting.” Within ten years, rabbits had become so prevalent in Australia that two million could be killed in a single year without greatly affecting the population. In these cases, unintended consequences are the norm, not the exception. From cane toads (What is it with invasive species and Australia?) to kudzu, humans have a pretty bad track record of taking account of all the variables.

So what could some of the unintended consequences be? Eventually stronger and more hardy mosquito populations, for one. Returning to the rabbit infestation of Australia, myxomatosis was introduced there in 1950 to infect rabbits and reduce their populations. In 1950, the survival rate was nearly 0% of those infected. Myxomatosis killed millions of Australian rabbits. Thanks to adaptation, however, myxomatosis now kills only 65% of those infected. Eventually, like what has happened in Europe, the lethality of myxomatosis will continue to decline. And in the end, you will be left with a hardier, healthier rabbit population.

In the same way, genetically modified mosquitoes breeding in the wild will probably eventually produce offspring that are immune to the deleterious effects that devastated earlier populations. And what if a few female mosquitoes are accidentally released? We just don’t know.

That’s not to say that we shouldn’t attempt to control mosquito populations, but perhaps we need to carefully consider releasing man-made genetic tamperings into the wild. We just don’t know what the unintended consequences could be. Would it not be better to err on the side of prudence?